Charleston / Duncan
Duncan has 4,310 residents (give or take 21) (ACS 2020-2024 5-year, table B01003, https://data.census.gov/table/ACSDT5Y2024.B01003?g=160XX00US4521265, checked 2026-10-19), about 651 people per square mile.
Duncan is about 191 miles from the Census center point for Charleston in a straight line and covers 6.621 square miles of land (Census 2024 Gazetteer internal points and land area, https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2024_Gazetteer/, checked 2026-10-19).
Of the 1,868 occupied homes in Duncan, 27% heat with natural gas, 1% with heating oil, 69% with electricity and 0% with propane (ACS 2020-2024 5-year, table B25040, https://data.census.gov/table/ACSDT5Y2024.B25040?g=160XX00US4521265, checked 2026-10-19).
Electricity already heats 69% of Duncan homes, ahead of gas at 27%, and a home on electric baseboard sees the biggest bill change from a heat pump because it replaces resistance heat one for one.
Duncan has about the Spartanburg County oil share of 1% and 1 points more electric heat than the county's 68% (ACS 2020-2024 5-year, table B25040, https://data.census.gov/table/ACSDT5Y2024.B25040?g=050XX00US45083, checked 2026-10-19).
Duncan has 2,054 housing units, 6% built before 1940 and 26% before 1980, with 51% built in 2000 or later (ACS 2020-2024 5-year, table B25034, https://data.census.gov/table/ACSDT5Y2024.B25034?g=160XX00US4521265, checked 2026-10-19).
Duncan has 16 points more homes built after 2000 than the county's 35% (ACS 2020-2024 5-year, table B25034, https://data.census.gov/table/ACSDT5Y2024.B25034?g=050XX00US45083, checked 2026-10-19).
The median Duncan home was built in 2001 (ACS 2020-2024 5-year, table B25035, https://data.census.gov/table/ACSDT5Y2024.B25035?g=160XX00US4521265, checked 2026-10-19) and the median home has 4.9 rooms (ACS 2020-2024 5-year, table B25018, https://data.census.gov/table/ACSDT5Y2024.B25018?g=160XX00US4521265, checked 2026-10-19).
64% of Duncan homes are single-family detached, 2% are in two- to four-unit buildings and 25% are in buildings of five or more units (ACS 2020-2024 5-year, table B25024, https://data.census.gov/table/ACSDT5Y2024.B25024?g=160XX00US4521265, checked 2026-10-19).
43% of Duncan homes are rented (ACS 2020-2024 5-year, table B25003, https://data.census.gov/table/ACSDT5Y2024.B25003?g=160XX00US4521265, checked 2026-10-19), so beside the 64% detached houses there is a real share of jobs where the landlord, not the resident, signs the quote.
Duncan has 8 points fewer detached houses than Spartanburg County overall (72%) and 16 points more five-plus-unit buildings than the county's 9% (ACS 2020-2024 5-year, table B25024, https://data.census.gov/table/ACSDT5Y2024.B25024?g=050XX00US45083, checked 2026-10-19).
43% of Duncan homes are rented (ACS 2020-2024 5-year, table B25003, https://data.census.gov/table/ACSDT5Y2024.B25003?g=160XX00US4521265, checked 2026-10-19), so the market splits between resident-led jobs where the occupant picks the system and landlord-led jobs where they do not, and the rebate paperwork differs.
51% of Duncan housing was built in 2000 or later (ACS 2020-2024 5-year, table B25034, https://data.census.gov/table/ACSDT5Y2024.B25034?g=160XX00US4521265, checked 2026-10-19), and homes that recent usually meet the insulation codes in place at the time, so a heat pump sized to the floor plan lands closer to the real load than it would in an older neighborhood.
No electric utility is on file for Duncan on this door yet, so this page does not name one; the name on the bill decides which rebate path applies.
Median household income in Duncan is $52,500 (ACS 2020-2024 5-year, table B19013, https://data.census.gov/table/ACSDT5Y2024.B19013?g=160XX00US4521265, checked 2026-10-19); many state and utility heat pump rebate programs set higher incentive tiers for income-qualifying households, so the household income on the application, not the town median, decides which level applies.
Heating design temperature: 22F. Source: ENERGY STAR Design Temperature Limit Reference Guide (2019 Edition), Spartanburg County row, 99% heating, PDF pages 105 to 107 of 141 (Revised 11/11/2020), https://www.energystar.gov/sites/default/files/Design%20Temperature%20Limit%20Reference%20Guide%20(2019%20Ed)%20-%20ENERGY%20STAR%20Single-Family%20New%20Homes_Rev11.pdf, fetched 2026-10-19, 99%.
That 22F figure is the Spartanburg County cold-day number a Duncan heat pump is sized against, so ask the installer to show the system's heating output at 22F, not at the milder rating-label temperature.
Ask for the heat-loss calculation room by room; the median Duncan home has 4.9 rooms and was built around 2001, and the count of heads and the tonnage follow the rooms and the insulation, not the square footage.
The form on this page is the follow-up for Duncan. The public number is the number the contractor quotes from.
No local contractor is named on this door for Duncan yet. A request from this page goes to the first licensed shop that takes the door.